It is a practice well known in the photographic art that in ordinary silver halide color photography, a color image is formed by developing a silver halide light-sensitive photographic material using a para-phenylenediamine color developing agent or the like in order to allow the oxidated developing agent with a dye forming coupler and to form a dye image.
Among processes for forming a color image, in a currently common process known as the subtraction method, a picture-taking sensitive material called a color negative film is usually exposed to record an image, and then, the material is subjected to developing according to the above-mentioned color developing process to obtain a negative image, and, next, the so-obtained negative image is printed onto a color paper using a printer.
A negative-type light-sensitive color photographic material usually has a multi-layer configuration, wherein three silver halide emulsion layers, are spectrally sensitized to have sensitivities to spectral regions of 400 to 500 nm, 500 to 600 nm, and 600 to 700 nm, respectively and the respective emulsion layers correspondingly contain a yellow coupler, magenta coupler and cyan coupler. Accordingly, an area sensitive to blue forms a yellow dye; an area sensitive to green forms a magenta dye; and an area sensitive to red forms a cyan dye; whereby a negative image is obtained. In order to obtain a color image, the so-obtained negative image is again printed onto a color paper that comprises a blue sensitive layer containing a yellow coupler, green-sensitive layer containing a cyan coupler, and red-sensitive layer containing a cyan coupler.
Unlike a block type dye regarded as an ideal dye of a subtraction color reproduction system (a dye having absorption is a specific spectral region), a dye used in color photography has significant degree of secondary absorption in a spectral region other than that intended. In other words, such a dye also absorbs light of an undesirable spectral region, and, therefore, satisfactory color reproduction becomes impossible without a specific countermeasure. Accordingly, in the case of a color negative film, for example, masking technique using a colored coupler is usually employed in order to enhance better, color reproduction.
Other countermeasures include negative spectral sensitivity compensation that is based both on the principle of three primary colors of the subtraction color reproduction system, and on the characteristics of human vision; and inter-image effect that is capable enhancing pure colors.
Thus, a color negative sensitive material incorporates various color correction means. However, there remains a problem unsolved; original signal data recorded after various corrections are printed onto a color paper, then color reproducibility of the negative-positive color reproduction system is deteriorated in this procedure, because a conventional color paper itself totally lacks color correction functions.
A light-sensitive direct positive photographic material used in a technical field such as a color copying machine cannot also be subjected to a masking technique using a colored coupler or the like because it is designed for direct appreciation with human vision of a user. Accordingly, this type of light-sensitive material fails to have sufficient color reproducibility, hence need for improvement thereof.
In the field of the silver halide light-sensitive photographic material, there is need for a sensitive material of improved graininess that further improves images being obtained. For example, in the case of the color negative material, though various techniques for improving color reproducibility are available, one important requirement is improved graininess.
As can be understood, the conventional color light-sensitive photographic material has a problem; color reproducibility thereof is not always satisfactory. This problem is especially serious in the case of a sensitive material for visual appreciation. At the same time, further improved graininess has been required of a color negative sensitive material.